error[E0774]: `derive` may only be applied to structs, enums and unions
  --> $DIR/issue-43106-gating-of-derive.rs:4:1
   |
LL | #[derive(Debug)]
   | ^^^^^^^^^^^^^^^^

error[E0658]: inner macro attributes are unstable
  --> $DIR/issue-43106-gating-of-derive.rs:7:20
   |
LL |     mod inner { #![derive(Debug)] }
   |                    ^^^^^^
   |
   = note: see issue #54726 <https://github.com/rust-lang/rust/issues/54726> for more information
   = help: add `#![feature(custom_inner_attributes)]` to the crate attributes to enable

error[E0774]: `derive` may only be applied to structs, enums and unions
  --> $DIR/issue-43106-gating-of-derive.rs:7:17
   |
LL |     mod inner { #![derive(Debug)] }
   |                 ^^^^^^^^^^^^^^^^^

error[E0774]: `derive` may only be applied to structs, enums and unions
  --> $DIR/issue-43106-gating-of-derive.rs:11:5
   |
LL |     #[derive(Debug)]
   |     ^^^^^^^^^^^^^^^^

error[E0774]: `derive` may only be applied to structs, enums and unions
  --> $DIR/issue-43106-gating-of-derive.rs:24:5
   |
LL |     #[derive(Debug)]
   |     ^^^^^^^^^^^^^^^^

error[E0774]: `derive` may only be applied to structs, enums and unions
  --> $DIR/issue-43106-gating-of-derive.rs:28:5
   |
LL |     #[derive(Debug)]
   |     ^^^^^^^^^^^^^^^^

error: aborting due to 6 previous errors

Some errors have detailed explanations: E0658, E0774.
For more information about an error, try `rustc --explain E0658`.